<%@page import="java.io.OutputStream"%>
<%@ page contentType="image/jpeg" import="java.awt.*, java.awt.image.*,java.util.*,javax.imageio.*"  pageEncoding="UTF-8"%> 
<%! 
    Color getRandColor(int fc,int bc) 
    { 
        Random random = new Random(); 
        if(fc>255) fc=255; 
        if(bc>255) bc=255; 
        int r=fc+random.nextInt(bc-fc); 
        int g=fc+random.nextInt(bc-fc); 
        int b=fc+random.nextInt(bc-fc); 
        return new Color(r,g,b); 
    } 
%> 
<% 
    response.setHeader("Pragma","No-cache"); 
    response.setHeader("Cache-Control","no-cache"); 
    response.setDateHeader("Expires", 0); 
    int width=60, height=20; 
    BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); 
    Graphics g = image.getGraphics(); 
    Random random = new Random(); 
    g.setColor(getRandColor(200,250)); 
    g.fillRect(0, 0, width, height); 
    g.setFont(new Font("Times New Roman",Font.PLAIN,18)); 
    g.setColor(getRandColor(160,200)); 
   
    for (int i=0;i<155;i++) {
        int x = random.nextInt(width); 
        int y = random.nextInt(height); 
        int xl = random.nextInt(12); 
        int yl = random.nextInt(12); 
        g.drawLine(x,y,x+xl,y+yl); 
    } 
    
    String sRand=""; 
    for (int i=0;i<4;i++){ 
        String rand=String.valueOf(random.nextInt(10)); 
        sRand+=rand; 
        g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110))); 
        g.drawString(rand,13*i+6,16); 
    } 
    //设置进入session属性
	//注意名称
    session.setAttribute("rand",sRand); 
    g.dispose(); 
    OutputStream os = response.getOutputStream();
    ImageIO.write(image, "JPEG", os); 
    
    //解决非法状态exception
    os.flush();  
    os.close();  
    os=null;  
    response.flushBuffer();  
    out.clear();  
    out = pageContext.pushBody();  
    }  
    catch(IllegalStateException e)  
    {  
    System.out.println(e.getMessage());  
    e.printStackTrace();  
%>